There are a large number of different types of processed food products such as frankfurters, bologna, salami, liverwurst, cheese rolls, turkey rolls, and the like manufactured throughout the world from a wide range of recipes and using many different types of processing conditions. A common feature of most categories of processed food products, particularly meat products, is that the mixture of ingredients of which the processed food product is prepared, commonly called an "emulsion", is stuffed into a casing. The food product can be processed while encased in the casing, and in many cases is then stored in the casing.
Casings most generally used are synthetic casings that may be of several different types and sizes depending on the category of food product to be prepared. In general, synthetic casings are supported or unsupported materials with the supported type, commonly called "fibrous food casing", utilized in the preparation of larger sizes of products such as turkey rolls. These casings can also be used to make somewhat smaller products such as chubs, e.g., sausages, which vary in diameter between 1 to 2 inches. Fibrous casing consists of a fibrous web, usually a non-woven paper, formed into a seamless tube, impregnated with viscose which is regenerated in situ.
Since there are so many differences in recipes for making processed food products, such as sausages, and such different modes of processing the different products, it is difficult to provide a casing that is acceptable for all uses. For example, a category of sausages is typified by liver sausage which is moist, relatively soft, has a substantially high fat content and is cooked, usually in hot water or steam, by the manufacturer. In this type of sausage, moisture must be protected against oxidation which causes undesirable discoloration. A suitable casing should, therefore, be impermeable to moisture and have a low rate of oxygen transmission. Thus various casings having a suitable coating adhered to the surface thereof are commercially available for use in such applications. Food casings such as, for example, disclosed in U.S. Pat. No. 2,961,323 are coated with materials, such as a polyvinylidene chloride copolymer, which are substantially impermeable to moisture and have low oxygen and gas transmission characteristics.
Cellulosic food casing used in the sausage industry are multifunctional in that they can be used as containers during the processing of the product and as protective wrapping for the finished product. The casing is often removed from the sausage after processing and the sausage sliced and repacked into smaller units. When the casing is removed from the meat mass, there is frequently a tendency for some meat to adhere to the casing and be torn from the sausage with the casing, thereby causing surface marring of the sausage. The marring may range from minor scuffing to severe scarring depending upon the type of meat product and conditions of processing and peeling. Thus in the use of this type casing, it may be advantageous to have an internally applied coating to the casing that will enable the casing to be easily removed from the meat mass encased therein.
In other applications, it may be desirable to have a different type of coating applied to the inner surface of a fibrous casing. For example, in stuffing sausage emulsion containing a substantially high fat content into a cellulose hydrate casing, it may be desirable to have a vinylidene resin coating applied on the inner surface of the casing so that when the sausage emulsion is processed, the outer surface of the casing after being wet can dry and shrink thus encasing the sausage properly to provide a plump, attractively shaped product.
For some applications, it may be desirable to have the internal or external surface of a casing coated with a layer such as a moisture-proof layer of polyvinyl chloride, polyolefins and substituted polyolefins as well as vinyls, polyesters, nylons, and suitable copolymers of the above. There are many methods presently available for internally coating a tubing as, for example, the "slugging" technique described in U.S. Pat. No. 3,378,379. There is also substantial knowledge available in the external coating art to permit the use of various coating materials to be applied to the external surface of tubing. It is known in the art that coated flexible tubings, such as internally or externally coated casings, can be turned inside out prior to stuffing the tubings with product.
German Patent Application No. 2,254,731 discloses another technique for stuffing shirred casings inside out so that the external surface of the shirred casings becomes the internal surface of the stuffed articles. Specifically, this application discloses a shirred casing in which one end of the casing is deshirred, closed and fed through the bore of the casing such that the closure means end up within the bore of the deshirred portion of the casing proximal the opposite end of the shirred casing. The double-walled casing so produced is thereby employed with conventional stuffing apparatus whereupon the casing is turned inside out during stuffing.
It is an object of the present invention to provide a shirred tubular casing having an internally disposed deshirred casing in which one end is an integral part of one end of the shirred casing and the opposite end of the deshirred casing being externally closed and disposed proximate the opposite end of the shirred casing.
Another object of the present invention is to provide a shirred tubular casing having an inturned disposed deshirred portion closed at one end and which is adaptable for being stuffed inside out in a manner such that the means used for closing the deshirred casing is on the outside of the casing.
Another object of the present invention is to provide a shirred tubular casing having an internally disposed deshirred casing portion that will easily turn inside out when being stuffed.
Another object of the present invention is to provide a process for producing a shirred tubular casing having a deshirred portion of the casing disposed within said casing and wherein said deshirred casing comprises an open end integrally part of one end of the shirred casing and closed end proximal the opposite end of the shirred casing with the closure means disposed outside the deshirred casing.